SD 

397 


A  Disease  of  Pines  Caused  by  Gronartiiun  Pyriforme 


BULLETIN    OF,    THE 


No.  2i7 

Contribution  from  the  Bureau  of  Plant  Industry,  Wm.  A.  Taylor,  Chief. 
July  20,  1915. 

(PROFESSIONAL  PAPER.) 


A   DISEASE   OF   PINES   CAUSED   BY   CRONARTIUM 

PYRIFORME. 

By  GEORGE  G.  HEDGCOCK,  Pathologist,  and  WILLIAM  H.  LONG,  Forest  Pathologist) 
Investigations  in  Forest  Pathology. 


CONTENTS. 


History  of  the  fungus 

Morphology  of  the  fungus 

Synonymy  and  description  of  the  fungus 

Inoculation  experiments  with  the  fungus 

Distribution  of  the  fungus 

Distribution  of  the  social  form 

Distribution  of  the  uredinial  and  telial 
forms... 


Page. 
1 
2 
3 
5 


Dissemination  of  the  fungus 

Effect  of  the  fungus  on  its  host  plants 

Effect  of  the  social  form  on  pines 

Effect  of  the  uredinial  and  telial  forms  on 

Comandra  plants 

Eradication  and  control  of  the  fungus 

Literature  cited... 


Page. 
12 
13 
13 

16 
16 
20 


HISTORY  OF  THE  FUNGUS. 

In  1875  Peck  (10)1  described  as  a  new  species  under  the  name  Peri- 
dermium  pyriforme  a  caulicolous  or  stem-inhabiting  Peridermium  with 
obovate  to  pyriform  spores  from  a  specimen  collected  by  J.  B.  Ellis 
(No.  2040).  In  1882  Ellis  issued  in  his  North  American  Fungi  under 
No.  1021  a  caulicolous  Peridermium  which  he  called  "Peridermium 
pyriforme  on  small  branches  of  Pinus  virginiana,"  and  in  the  Ellis 
Herbarium,  now  at  the  New  York  Botanical  Garden  is  a  specimen 
labeled  "Peridermium  pyriforme  on  small  branches  of  Pinus  rigida, 
Newfield,  New  Jersey,  May,  1890."  Both  of  these  latter  specimens 
appear  to  be  Peridermium  comptoniae;  at  any  rate,  neither  of  them  is 
the  true  P.  pyriforme  originally  described  by  Peck.  Arthur  and  Kern 
(1)  in  1906  described  as  P.  pyriforme  Peck  what  is  now  known  as  P. 
comptoniae. 

In  1913  the  writers  received  from  Prof.  E.  Bethel  a  caulicolous 
species  of  Peridermium  on  Pinus  contorta,  which  they  described  as  a 

1  Reference  is  made  by  number  to  "  Literature  cited,"  p.  20. 

NOTE.— This  bulletin  discusses  an  important  disease  of  pines  which  is  now  for  the  first  time  fully  de- 
scribed. It  is  intended  for  circulation  among  botanists,  foresters,  nurserymen,  State  inspectors,  and  horti- 
culturists. 


93041°— Bull.  247— U 


437637 


'-s;  DEPARTMENT  OF  AGRICULTURE. 

new  specie's,-  "PvndermiuSri'beitieli  (6).  The  type  material  P.  pyri- 
forme  was  not  accessible  at  the  time  the  article  was  prepared,  as  all 
of  Peck's  specimens  were  packed  up  and  in  transit  from  the  old  to 
the  new  quarters  of  the  New  York  State  Museum.  The  writers  there- 
fore had  to  depend  upon  Arthur  and  Kern's  published  statement  con- 
cerning this  species  (1,  p.  420),  The  spore  measurements  also  of  the 
typical  P.  pyriforme  did  not  correspond,  since  the  length  of  spores  of 
the  eastern  species  as  given  by  Peck  in  his  original  description  was 
too  great.  While  this  article  by  the  writers  (6)  was  in  press,  Arthur 
and  Kern  published  an  article  (2)  in  which  they  discarded  their  earlier 
interpretation  of  P.  pyriforme  and  admitted  that  there  is  a  species  of 
Peridermium  with  typical  "pyriform,  obovate,  or  oblong-pyriform 
spores,"  just  as  Peck  had  originally  described  it  in  1875  (10),  and 
that  then*  original  assignment  of  P.  pyriforme  Peck  to  what  is  now 
known  as  P.  comptoniae  was  an  error.  They  also  suggested  that  the 
alternate  stages  of  this  Peridermium  would  probably  be  found  on 
species  of  Comandra. 

Orton  and  Adams  (9),  in  1914,  published  an  article  on  Peridermium 
from  Pennsylvania,  in  which  they  discussed  Peridermium  comptoniae 
and  P.  pyriforme.  They  described  the  finding  of  a  caulicolous  species 
of  Peridermium  at  Charteroak,  Huntingdon  County,  Pa.,  on  the 
trunks  of  Pinus  pungens,  which  proved  to  be  the  true  Peridermium 
pyriforme  of  Peck.  Subsequently  Oronartium  comandrae  was  found 
within  40  feet  of  the  infected  pines  and  the  conclusion  reached  that 
this  Cronartium  is  the  alternate  stage  of  Peridermium  pyriforme. 
They  also  state  that  P.  beiheli  is  probably  a  synonym  of  P.  pyriforme. 
In  May,  1914,  Arthur  and  Kern  in  a  general  discussion  of  the  North 
American  species  of  Peridermium  inhabiting  pines  (3)  gave  the  syn- 
onymy of  P.  pyriforme,  a  technical  description,  and  an  explanation 
of  their  change  of  opinion  regarding  the  species. 

In  June,  1914,  the  writers  published  culture  data  (8)  showing  that 
successful  sowings  of  the  seciospores  of  Peridermium  pyriforme  had 
been  made  on  Comandra  umbellata,  thus  completing  the  life  cycle  of 
this  interesting  rust  and  proving  that  its  alternate  stage  was  the 
Cronartium  found  on  Comandra. 

MORPHOLOGY  OF  THE  FUNGUS. 

The  macroscopic  characters  of  Peridermium  pyriforme  are  practi- 
cally identical  on  all  the  hosts  examined  by  the  writers,  but  there 
are  some  differences  in  the  microscopic  characters,  especially  in  the 
shape  and  size  of  the  seciospores.  This  difference  in  size  and  shape 
of  the  spores  may  be  due  to  the  influence  of  the  secial  host;  that  is, 
they  may  vary  according  to  the  species  of  Pinus  which  the  Perider- 
rium  inhabits.  In  specimens  of  the  rust  on  Pinus  contorta  (PL  I, 


A   DISEASE   OF   PINES   CAUSED  BY   CRONARTIUM    PYRIFORME. 


fig.  4)  from  Colorado,  some  of  the  seciospores  are  very  short  and 
slightly  acuminate,  while  many  are  ellipsoid  or  even  globoid  (PL  I, 
fig.  3).  In  specimens  on  Pinus  pungens  from  Pennsylvania  many  of 
the  spores  are  nearly  twice  as  long  as  those  from  Pinus  contorta, 
the  acumination  is  very  marked,  and  the  spores  are  rarely  ellipsoid 
(PI.  I,  fig.  2). 

Peck's  type  material  of  Peridermium  pyrijorme  is  in  the  New 
York  State  Museum,  at  Albany,  N.  Y.  It  consists  of  a  split  branch 
4  cm.  long,  1  cm.  thick  at  one  end  and  0.5  cm.  thick  at  the  other; 
the  weak,  fragile  peridia  barely  protrude  beyond  the  bark.  The 
split  surface  of  the  twig  is  glued  to  the  yellow  paper  bearing  one  of 
the  legends.  The  specimen  is  in  fairly  good  condition  and  most  of 
the  essential  characters,  both  macroscopic  and  microscopic,  can  be 
determined  from  it.  What  appears  to  be  the  other  half  of  this  speci- 
men is  at  the  New  York  Botanical  Garden,  Bronx  Park,  N.  Y.;  but 
it  is  much  insect  eaten  and  but  little  can  be  determined  from  it. 

The  type  material  at  Albany  bears  the  following  legends  on  the 
box:  "Peridermium  pyriforme,  Newfield,  N.  J.  Ellis  #2040."  On 
the  original  wrapper  is  "Peridermium  pyriforme  on  pine  limbs  in 
the  spring,  Newfield,  N.  J.  .0015-.0025.  No.  2040  Ellis."  This 
legend  is  in  two  parts.  The  name  is  in  Peck's  handwriting,  with  a 
drawing  of  a  spore  and  size  of  spores  in  pencil,  while  the  host,  loca- 
tion, and  number  of  the  specimen  are  in  ink  and  are  in  Ellis's  hand- 
writing. The  word  "type"  is  not  in  the  original  legend.  The  fol- 
lowing is  Peck's  original  description  of  Peridermium  pyriforme  (10) 
and  his  remarks  on  the  same : 

Peridia  erumpent,  large,  white  when  evacuated,  the  cells  subrotund,  with  a  paler 
margin,  marked  with  radiating  striations,  spores  obovate,  pyriform,  or  oblong- 
pyriform,  acuminate  below,  .0015-.0025  inch  long. 

Bark  of  pine  branches.  The  specimen  is  labeled  "Newfield,  N.  J.,"  but  Mr.  Ellis 
informs  me  that  it  may  have  been  collected  in  Georgia  and  placed  by  accident  among 
his  New  Jersey  specimens. 

In  the  dried  specimens  the  peridia  are  mostly  compressed,  about  one-fourth  of  an 
inch  long,  and  scarcely  exserted  above  the  surface  of  the  bark.  The  spores  are  pale 
yellow,  but  probably  they  are  more  highly  colored  when  fresh.  The  acumination  is 
generally  acutely  pointed,  and  it  is  sometimes  so  elongated  as  to  make  the  spore 
appear  clavate.  It  is  one  of  the  most  distinctive  features  of  the  species. 

SYNONYMY  AND  DESCRIPTION  OF  THE  FUNGUS. 

Cronartium  pyriforme  (Peck)  Hedge,  and  Long,  1914,  Alternate  Stage  of  Peridermium 

Pyriforme. 

Cronartium  asclepiadeum  thesii  Berk.,  1845,  in  Lond.  Jour.  Bot.,  v.  4,  p.  311. 
Peridermium  pyriforme  Peck,  1875,  in  Bui.  Torrey  Bot.  Club,  v.  6,  No.  2,  p.  13. 
Caeoma  comandrae  Peck,  1884,  in  Bui.  Torrey  Bot.  Club,  v.  11,  No.  5,  p.  50. 
Cronartium  thesii  (Berk.)  Lagerh.,  1895,  in  Troms0  Mus.  Aarsh.,  v.  17,  p.  94. 
Peridermium  betheli  Hedge,  and  Long,  1913,  in  Phytopathology,  v.  3,  No.  4,  p.  251. 

Pycnia  unknown. 


BULLETIN   247,   U.    S.    DEPARTMENT    OF   AGRICULTURE. 

caulicolous,  appearing  on  branches  or  trunks,  forming  le- 
sions or  fusiform  swellings  2  to  30  cm.  long  (PL  II,  fig.  3);  sori  scat- 
tered or  somewhat  confluent  in  small  groups,  rounded  or  irregular , 
2  to  6  mm.  long  by  2  to  4  mm.  wide  by  1  to  2  mm.  high;  peridium 
usually  only  slightly  protruding  from  the  bark,  bladdery,  subhemi- 
spherical,  rupturing  irregularly  along  the  top  and  sides,  without  con- 
colorous  processes,  about  2  cells  thick,  outer  surface  minutely  and 
rather  closely  verrucose,  inner  surface  also  rather  closely  verrucose 
but  with  longer  tubercles;  peridial  cells  with  a  radially  striate  mar- 
gin, not  easily  torn  apart,  those  of  the  inner  layer  often  irregularly 
compressed,  walls  thin,  2  to  4  /z  in  thickness,  lumen  large;  cells  in 
the  upper  portion  of  the  peridium  ovate,  15  to  20  by  22  to  42  //,  in 
the  lower  portion  ellipsoid  to  ovate,  16  to  20  by  40  to  60  /*;  a3cio- 
spores  very  variable  in  size  and  shape,  subglobose,  obovate,  ellipsoid, 
pyriform  or  even  subclavate  on  some  hosts,  more  or  less  acuminate 
at  the  basal  end,  occasionally  at  both  ends  (PL  I,  figs.  1,  2,  and  3), 
15  to  27  by  25  to  74  /*,  average  for  160  seciospores  21.6  by  57.5  /i, 
walls  colorless,  thicker  at  both  ends  than  in  the  middle,  2  to  4  /* 
thick,  rather  densely  verrucose  with  small  irregular  tubercles  which 
in  narrow  ellipsoid  spores  are  often  arranged  in  irregular  almost  paral- 
lel lines  or  with  a  ridgelike  marking,  which  gives  the  surface  a  reticu- 
late appearance,  no  smooth  spot  present;  cell  contents  of  the  secio- 
spores  orange  yellow  when  fresh. 

Found  on  Pinus  contorta  Loud.,  P.  divaricata  (Ait.)  Du  Mont  du 
Cours.,  P.  ponderosa  Laws.,  P.  ponderosa  scopulorum  Sudw.,  P. 
pungens  Michx.,  and  Pinus  sp. 

Uredinia  amphigenous  or  hypophyllous,1  scattered  or  densely  gre- 
garious, on  pallid  areas,  pustular,  125  to  200  /*  in  diameter,  dehiscent 
by  a  central  opening  or  pore;  peridium  delicate;  urediniospores 
broadly  elliptical  to  globoid,  16  to  21  by  19  to  25  ^,  average  for  10 
spores  17.8  by  20  //,  walls  nearly  colorless  and  sparsely  but  minutely 
echinulate,  1.5  to  2  /*  thick. 

Telial  columns  amphigenous  or  hypophyllous,1  caulicolous,  cylin- 
drical, 80  to  115  n  thick,  about  1  mm.  in  length;  teliospores  oblong 
to  cylindrical,  obtuse  to  truncate  at  one  or  both  ends,  12  to  16  by  28 
to  40  /JL,  average  for  10  spores  14  by  32.7  /*,  walls  smooth,  nearly 
colorless. 

Found  on  Comandra  pallida  A.  DC.,  C.  umbellata  (L.)  Nutt.7  and 
C.  richardsiana  Fernald  (?). 

In  the  preceding  description  by  the  junior  writer,  the  aecial  char- 
acters (Peridermium)  are  taken  from  the  specimens  named  in  Table 
II  on  Pinus  contorta,  P.  ponderosa,  P.  ponderosa  scopulorum,  and 
P.  pungens.  The  uredinial  and  telial  characters  (Cronartium)  are 

1  Amphigenous  on  -Comandra  pallida,  hypophyllous  on  Comandra  umbellata. 


Bui.  247,  U.  S.  Dept.  of  Agriculture. 


PLATE  I. 


>£CIOSPORES  OF  CRONARTIUM  PYRIFORME  AND  A  TWIQ  OF  PINUS  CONTORTA. 

FIG.  1.— yEciospores  of  Cronartium  pyrijorme,  from  the  type  specimen  on  Pinus  sp.  at  Albany, 
N.  Y.  ( Microphotograph. )  FIG.  2. — ^ciospores  of  Cronartium  pyrijorme  from  Pinus  pun- 
gens,  collected  near  Greenwood  Furnace,  Pa.  (Microphotograph.)  These  closely  resemble 
the  type.  FIG.  3. — ^Eciospores  of  Cronartium  pyrijorme  from  Pinus  contorta,  near  Eldorado 
Springs,  Colo.,  from  the  same  tree  as  the  type  of  Peridermium  betheli  (microphotograph), 
showing  the  variation  in  the  shape  of  the  spores  on  this  pine  from  those  of  the  type 
specimen  in  figure  1.  FIG.  4. — A  twig  of  Pinus  contorta,  showing  the  secia  and  peridia  of 
the  fungus  Peridermium  pyrijorme  (P.  betheli)  on  a  slightly  swollen  portion.  (About  natural 
size.) 


Bui.  247,  U.  S.  Dept.  of  Agriculture. 


PLATE  II. 


INJURIES  TO  PINES  PRODUCED  BY  CRONARTIUM  PYRIFORME. 

FIG.  1.— A  slight  hypertrophy  of  the  trunk  of  a  small  tree  of  Pinus  pungcns  produced  by  the 
seciaof  Cronartium  pyriforme.  ( About  one-third  natural  size.)  FIG.  2.— Openings  produced 
by  the  rupturing  of  the  bark  of  Pinus  pungcns  by  the  maturing  of  the  secia  of  Cronartium 
(Peridermium)  pyriforme.  (About  one-third  natural  size.)  FIG.  3.— A  twig  of  Pinus  contorta, 
showing  a  fusiform  swelling  produced  by  Cronartium  (Peridermium)  pyriforme  on  this  species 
of  tree.  Similar  fusiform  swellings  are  produced  by  the  fungus  on  Pinus  ponder -osa.  (About 
one-half  natural  size.) 


A  DISEASE   OF   PINES    CAUSED  BY   CEONARTIUM    PYEIFORME. 


taken  from  specimens  of  the  fungus  on  leaves  of  Comandra  umbel- 
late, obtained  by  inoculations  with  seciospores  from  Pinus  pungens 
from  Greenwood  Furnace,  Pa. 

INOCULATION  EXPERIMENTS  WITH  THE  FUNGUS. 

Table  I  gives  complete  inoculation  data  for  this  fungus  on  Comandra 
umbellata.  Successful  inoculations  were  made  with  seciospores  from 
two  hosts,  Pinus  ponderosa  and  Pinus  pungens,  collected  from  three 
widely  separated  localities  in  the  States  of  Washington,  California, 
and  Pennsylvania.  In  each  instance  control  plants  of  the  same 
species  were  used,  and  all  remained  free  from  infection.  Unsuccessful 
inoculations  were  made  with  asciospores  from  Pinus  contorta  (Peri- 
dermium  ~befheli)  both  during  1913  and  1914.  In  1914  the  failure  to 
infect  might  have  been  due  to  the  extreme  high  temperature  of  the 
greenhouse  at  the  time  the  inoculation  experiments  were  performed. 
However,  the  failure  for  two  successive  seasons  to  infect  Comandra 
with  the  seciospores  from  Pinus  contorta  may  indicate  that  the  rust 
on  this  host  is  a  different  species  from  Peridermium  pyriforme,  since 
the  shape  and  size  of  the  seciospores  (P.  betheli',  PI.  I,  fig.  3)  from 
Pinus  contorta  are  different  from  those  of  the  type  specimen  of  this 
rust  (PI.  I,  fig.  1).  The  writers,  in  the  absence  of  proof  from  inocula- 
tions, assume  for  the  present  that  these  morphological  differences  may 
be  due  to  the  host  and  therefore  are  not  of  sufficient  importance  to 
warrant  classifying  Peridermium  betheli  as  distinct  from  P.  pyriforme. 

TABLE  I. — Results  of  inoculations  with  the  seciospores  of  Cronartium  pyriforme. 


^cial  host,  serial  num-      qnApi|llQ  innmlatprl 
ber,  and  locality.           bPec 

Date  of 
inocula- 
tion. 

Results. 

Collector. 

Ure- 
dinia. 

Telia. 

Degree  of 
infection. 

Pinus  contorta: 
8500,   Eldorado 
Springs.  Colo. 
8500,i       Eldorado 
Springs,  Colo. 
8514,     Allenspark, 
.    Colo. 
Do 

Comandra  umbellata.  . 
Comptonia  asplenifolia 
Comandra  umbellata.  . 
Castilleja  linearis 

1913 
June  18 

...do.... 
June  27 
do 

No  infection.  .  . 
do  
do 

Bethel. 
Do. 
Do. 
Do. 

Fisher. 

Do. 

Boyce. 

Hedgcock. 
Do. 

Do. 
Do. 

Do. 
Do. 
Do. 

Do. 
Do. 





do 

Pinus  ponderosa: 
12467,  Wenatchee, 
Wash. 
Do 

Comandra  umbellata.  . 
do 

1914 
May   27 

May   30 
May   28 

May   29 
May  30 

...do.... 
June    1 

June    2 
...do.... 
June    3 

July     3 
...do.... 

1914 
June  5 

June  9 
June  6 

June  7 
June  10 

June  11 
...do.. 

June  12 
June  13 
...do.. 

1914 
June  28 

July     4 
July     5 

June  30 
July   15 
.  do  .. 

Sparse2  

do  
do  

12468.    Rocky 
Gulch,  Cal. 
Pinus  pnn^ens: 
15444,  Greenwood 
Furnace,  Pa. 
15455,  Greenwood 
Furnace,  Pa. 
Do  
15462,  Greenwood 
«     Furnace,  Pa. 
Do 

do  
do  

Very      abun- 
dant. 
do  

..  do  

.      do  

do  
do  

do 

July     1 

July     4 
July     8 
July     5 

Sparse 

Abundant  3  .  .  . 
do  

Do  

Do 

do  

do 

Pinus  contorta: 
15550,    Eldora, 
Colo. 
Do 

do  

Ribes  longiflorum  

No  infection  <.. 
do  

1  Type  of  Peridermium  bethcli. 

1  Sparse  here  means  less  than  six  sori. 


3  Telia  immature. 

4  Inoculation  made  in  very  hot  weather. 


6 


BULLETIN   247,  U.    S.   DEPARTMENT   OF   AGRICULTURE. 


A  study  of  Table  II  and  of  figures  1  and  2  of  Plate  I  shows  some 
very  interesting  facts.  For  instance,  the  shape  and  size  of  the  spores 
from  the  type  material  (PL  I,  fig.  1)  and  those  from  Pinus  pungens 
(PI.  I,  fig.  2)  are  practically  identical,  since  the  range  in  size  for  20 
spores  of  the  type  is  19  to  25.6  //  by  41.6  to  73.6  fi  with  an  average 
for  20  spores  of  23.4  by  58.6;*,  and  for  20  spores  from  Pinus  pungens 
the  range  is  19  to  25.6  /*  by  42  to  73.6  p.  with  an  average  for  20  spores 
of  23.1  by  59.1  //.  This  close  similarity  in  size  and  shape  would 
indicate  that  the  type  may  have  been  on  Pinus  pungens,  but  this 
does  not  seem  probable  if  the  type  really  came  from  Newfield,  N.  J., 
as  Pinus  pungens  has  not  been  reported  from  this  locality,  although 
Britton  (4)  reports  it  as  abundant  1  mile  east  of  Sergeantsville,  in 
Hunterdon  County.  It  is  possible  that  sporadic  or  introduced 
specimens  of  Pinus  pungens  may  have  been  growing  near  Newfield 
at  the  time  the  collection  of  the  type  specimen  of  Peridermium 
pyriforme  was  made.  The  alternate  stage  of  the  rust,  Cronartium 
pyriforme,  on  Comandra  umbellata  was  collected  at  Newfield,  N.  J., 
by  Ellis  in  August,  1879,  and  issued  by  him  in  North  American 
Fungi  under*  the  number  1082.  This  indicates  that  the  type  material 
of  Peridermium  pyriforme  came  from  New  Jersey. 

TABLE  II. — Measurements,  shape,  etc.,  of  the  seciospores  of  Cronartium  pyriforme. 


JEcial  host,  serial  number, 
and  locality. 

Measurement  (microns). 

Shape. 

Acumination. 

Range  in  size. 

Average  lor 
20  spores. 

Pinus  pungens: 
15462,    Greenwood    Fur- 
nace, Pa. 

Pinus  sp.: 
Type,  Newfield,  N.  J.  (?). 

Pinus  ponderosa: 
15556,  near  Darby,  Mont.  . 

12467,  Wenatchee,  Wash  .  . 
1246S,  Rocky  Gulch,  Cal.. 

Pinus  ponderosa  scopulorum: 
12470,     Crook     National 
Forest,  Ariz. 
Pinus  contorta: 
15550,  Eldora,  Colo  

19  to  25.6  by  42  to 
73.6. 

19  to  25.6  by  41.6 
to  73.6. 

19  to  25.6  by  38  to 
64. 

18  to  25.6  by  38  to 
64. 
20.8  to  25.6  by  35 
to  70.4. 

19  to  27  by  32  to  64. 

15  to  25.6  by  25  to 
45. 
15  to  26  by  25  to  48. 

23.1  by  59.1.. 
23.4  by  58.6.. 

22.4  by  48.6.. 

21.1  by  51.5.. 
23.9  by  54.5.. 

21.8  by  44.3.. 

18.1  by  40.2.. 
20  by  43 

Obovate  or  pyri- 
form  to  subcla- 
vate  or  spatulate. 

Obovate  to  pyri- 
form  or  subcla- 
vate. 

Obovate  to  pyri- 
form    or   rarely 
ellipsoid. 
Obovate  to  pyri- 
form. 
do 

Often     very    long 
(PL  I,  fig.  2). 

Often    very    long 
(PI.  I,  fig.  1).     ' 

Often  not  very  pro- 
nounced. 

Do. 
Do. 

Usually  very  short. 

Usually  very  short 
(PL  I,  fig.  3). 
Usually  very  short. 

Ellipsoid  or  obo- 
vatetopyriform. 

.      do 

8500,   Eldorado  Springs, 
Colo. 

do 

The  senior  writer,  during  August,  1914,  visited  Newfield  and  several 
other  localities  in  the  same  region.  He  found  the  same  species  of 
pine  here  that  are  known  to  occur  in  southern  New  Jersey  and  that 
probably  were  present  at  the  time  of  the  Ellis  collection,  viz,  Pinus 
echinata,  P.  rigida,  and  P.  virginiana.  None  of  these  were  found  by 
him  to  be  diseased  with  the  Peridermium  of  Cronartium  pyriforme. 


A  DISEASE   OF   PINES    CAUSED  BY   CEONAKTIUM    PYRIFORME.          7 

Comandra  umbellata  observed  in  a  number  of  these  localities  was  also 
free  from  the  rust. 

In  1914  the  senior  writer  found  Pinus  pungens,  P.  rigida,  and  P. 
virginiana  closely  associated  in  a  mixed  forest  near  Greenwood  Fur- 
nace, Pa.  In  this  instance  Pinus  pungens  was  attacked  by  Peri- 
dermium pyriforme  so  badly  that  in  some  places  more  than  50  per 
cent  of  the  trees  were  killed,  and  although  Comandra  umbellata  plants 
bearing  the  telial  form  of  the  rust  were  present  in  abundance,  no  pines 
of  either  of  the  other  species  were  diseased.  This  indicates  that  these 
two  species  of  trees  are  immune  and  that  neither  can  be  the  host  for 
the  type  specimen  that  Ellis  found  at  Newfield.  Of  the  five  species 
of  pines  known  to  be  the  a3cial  host  of  this  fungus,  not  one  is  a  strictly 
three-needle  pine.  All  have  either  two  or  two  to  three  needles  in  the 
leaf  clusters.  This  makes  it  seem  improbable  that  Pinus  rigida  was 
the  host  of  the  type  material.  Pinus  echinata  is  a  two  to  three  needle 
pine  found  in  southern  New  Jersey,  and  this  species  may  have  been 
the  host  of  Ellis's  type. 

The  cultural  work  done  by  the  writers  with  Peridermium  pyriforme 
Peck  proving  it  to  be  the  secial  stage  of  Cronartium  pyriforme  (Peck) 
Hedge,  and  Long  on  species  of  Comandra  completes  the  life  history 
of  all  the  caulicolous  species  of  Peridermium  as  now  recognized  in  the 
United  States.  There  are  four  native  and  one  introduced  species  and 
each  constitutes  the  aecial  stage  of  a  species  of  Cronartium : 

(1)  Peridermium  pyriforme,  which  is  the  secial  stage  of  Cronartium  pyriforme. 

(2)  Peridermium  cerebrum  Peck  is  the  secial  stage  of  Cronartium  cerebrum  (Peck) 
Hedge,  and  Long  on  species  of  Quercus  and  Castanopsis.     This  is  a  well-recognized 
eastern  species  and,  including  its  western  form,  Peridermium  harknessii  Moore,  is  the 
only  native  gall-forming  Peridermium  in  the  United  States.     P.  harknessii  on  Pinus 
radiata  Don  is  synonymous  with  Peridermium  cerebrum,  since  it  is  associated  with 
Cronartium  cerebrum  on  Quercus  agrifolia  Nee  on  the  Monterey  Peninsula  in  California, 
The  other  forms  of  Peridermium  harknessii  may  not  belong  here,  and  until  cultural 
proof  of  their  identity  with  P.  cerebrum  is  obtained,  the  forms  on  Pinus  ponderosa, 
Pinus  contorta,  and  other  western  pines  remote  from  species  of  Quercus  and  Cas- 
tanopsis can  only  be  doubtfully  referred  here. 

(3)  Peridermium  comptoniae  (Arth.)  Orton  and  Adams,  a  well-known  eastern  species, 
usually  occurring  on  the. pitch  pine  (Pinus  rigida  Mill.)  in  the  eastern  and  north- 
eastern United  States,  but  also  attacking  two  to  three  needle  species,  is  the  secial 
stage  of  Cronartium  comptoniae  Arth.  which  attacks  Comptonia  peregrina  (L.)  Coult. 
and  Myrica  gale  L. 

(4)  Peridermium  filamentosum  Peck  on  Pinus  ponderosa  and  Pinus  contorta  is  the 
secial  stage  of  Cronartium  filamentosum  (Peck)  Hedge.,  which  attacks  a  number  of 
species  of  Castilleja  in  the  western  United  States  over  a  wide  region,  ranging  from  the 
Rocky  Mountains  to  the  Pacific  coast.     Peridermium  stalactiforme  Arth.  and  Kern 
and  Cronartium  coleosporioides  (Dietel  and  Holway)  Arth.  and  Kern  are  synonymous 
with  this  species. 

(5)  Peridermium  strobi  Kleb.,  an  introduced  species,  is  the  secial  stage  of  Cronar- 
tium ribicola  Fisch.  de  Waldh.,  which  attacks  many  species  of  Ribes.     In  Europe  this 
Peridermium  attacks  several  species  of  white  (5-needle)  pine.     In  the  United  States 
it  has  been  found  on  only  one  species,  Pinus  strobus  L. 


8 


BULLETIN   247,   U.    S.   DEPARTMENT   OF   AGRICULTURE. 


For  a  number  of  years  Prof.  E.  Bethel  has  collected  from  the  leaves 
of  Ribes  longiflorum  at  Denver,  Boulder,  and  elsewhere  in  Colorado 
a  species  of  Cronartium  which  is  apparently  not  identical  with  the 
European  Cronartium  ribicola.  The  senior  writer  collected  abundant 
specimens  of  the  uredinial  and  telial  forms  of  this  rust  both  at  Boulder 
and  Denver,  Colo.,  in  October,  1914.  The  telia  of  this  Cronartium 
are  larger,  more  abundant,  and  much  more  conspicuous  than  those 
of  the  European  species.  Although  the  fungus  has  been  epidemic 
for  several  years  on  the  Chautauqua  grounds  near  Boulder,  two  young 
white  pines  (Pinus  strobus)  on  the  grounds  not  far  from  the  diseased 
Ribes  were  free  from  the  disease.  This  species  apparently  is  able  to 
winter  over  on  Ribes  plants  in  the  uredinial  form.  Itrmay  yet  be 
found  that  the  aecial  form  is  a  Peridermium  on  one  of  our  native 


pines. 


DISTRIBUTION  OF  THE  FUNGUS. 


DISTRIBUTION  OF  THE  /ECIAL  FORM.* 


The  secial  form  of  the  fungus,  Peridermium  pyriforme,  is  widely 
distributed  in  the  United  States,  having  been  found  in  10  States: 


*~r-l        /  v  *  "V_ 

**/   74-jJr  r^ 


FIG.  1.— Outline  sketch  map  of  the  United  States,  showing  the  known  distribution  of  Cronartium  pyri- 
forme. Localities  where  collections  of  the  different  forms  of  the  fungus  have  been  made  are  indicated  as 
follows:  v,  -3Scial  form  on  species  of  pines;  •%  uredinial  and  telial  forms  on  species  of  Comandra;  X,  all 
forms. 

Arizona,  California,  Colorado,  Montana,  New  Jersey,  Pennsylvania, 
South  Dakota,  Washington,  Wisconsin,  and  Wyoming  (fig.  1);  and 
when  a  more  careful  search  is  made  for  the  fungus,  in  the  light  of  our 
present  knowledge,  it  will  no  doubt  be  found  to  have  a  much  more 
general  distribution  in  this  country.  It  has  also  been  found  in 
Alberta  and  British  Columbia. 

i  All  specimens  cited  except  those  marked  with  a  star  (*)  have  been  examined  by  one  of  the  writers. 


A   DISEASE   OF   PINES   CAUSED   BY   CKONAETIUM    PYRIFOBME.          9, 

DISTRIBUTION  IN  THE  DOMINION  OP  CANADA. 

Alberta. — On  Pinus  contorta  (P.  murrayana):  *  Devil's  Lake, 
Banff,  by  Holway  (3,  p.  127),  in  1907. 

British  Columbia.— On  Pinus  ponderosa:  *  Vernon,  by  Brittain, 
in  1913. 

DISTRIBUTION  IN  THE   UNITED  STATES. 

New  Jersey. — On  Pinus  sp.:  (Type)  Newfield,  by  Ellis  (2040),  in 
1882  (Herbarium  New  York  State  Museum). 

Pennsylvania. — On  Pinus  pungens:  Charteroak,  by  Orton  and 
Adams,  in  1913  (F.  P.1  15129);  Greenwood  Furnace,  by  Hedgcockf 
in  1914  (F.  P.  15444,  15455,  and  15462);  Petersburg,  Huntingdon 
County,  by  Hedgcock,  in  1914  (F.  P.  15483). 

Wisconsin. — On  Pinus  divaricata:  *  Douglas  County,  by  Davis. 

South  Dakota. — On  Pinus  ponderosa  scopulorum:  *  Rockerville,  by 
White;  Black  Hills  near  Custer,  by  Hedgcock  and  Phillips  (F.  P. 
15826)  and  by  Hedgcock  (F.  P.  15801),  in  1914. 

Wyoming.— On  Pinus  contorta:  Dubois,  by  C.  E.  Taylor,  in  1914 
(F.  P.  15797). 

Colorado. — On  Pinus  contorta  (P.  murrayana) :  *  Gatos  (collector 
not  given),  in  1906  (3,  p.  126-127);  Eldorado  Springs  (F.  P.  8500), 
type  of  Peridermium  betheli,  Lake  Eldora  (F.  P.  8511),  AUenspark 
(F.  P.  8502  and  8514),  Arrow  (F.  P.  8515  and  8494),  by  Bethel,  in 
1913;  Eldora  (F.  P.  15550),  by  Bethel,  in  1914. 

On  Pinus  ponderosa  scopulorum:  Monument,  by  Hedgcock,  in 
1912;  AUenspark,  by  Bethel,  in  1913  (F.  P.  8504,  8505,  8510,  and 
8451). 

Montana. — On  Pinus  ponderosa:  Darby,  by  Weir,  in  1914  (F.  P. 
15556). 

Washington. — On  Pinus  ponderosa:  Wenatchee,  by  D.  F.  Fisher, 
in  1914  (F.  P.  12467). 

On  Pinus  sp.:  *  Seattle,  by  Bonser  (3,  p.  127),  in  1906. 

California. — On  Pinus  ponderosa:  Trinity  National  Forest,  by 
Box,  in  1912;  Rocky  Gulch,  Siskiyou  County,  by  Meinecke,  in '1913; 
by  Boyce,  in  1914  (F.  P.  12468);  Mills  Ranch,  Goosenest  Mountain, 
Siskiyou  County,  by  Boyce,  in  1914  (F.  P.  15678  and  15680);  Cas- 
tella,  Shasta  County;  Weaverville  and  Brown  Creek,  Trinity  County, 
by  Boyce,  in  1914. 

Arizona. — On  Pinus  ponderosa  scopulorum:  Crook  National  Forest, 
by  Swift,  in  1914  (F.  P.  12470). 

DISTRIBUTION  OF  THE  UREDINIAL  AND  TELIAL  FORMS. 

Cronartiu'm  pyriforme,  representing  both  the  uredinial  and  telial 
forms  of  the  fungus,  has  been  collected  more  frequently  and  over  a 
greater  range  of  terrritory  than  the  ascial  form.  It  has  been  found  in 

1  Forest-Pathology  Investigations  number. 
93041°— Bull.  247—15 2 


10  BULLETIN    247,   U.    S.    DEPARTMENT   OF    AGRICULTURE. 

Quebec  and  Ontario  in  the  Dominion  of  Canada  and  in  the  United 
States  in  the  following  States:  California,  Colorado,  Illinois,  Massa- 
chusetts, Michigan,  Missouri,  Montana,  Nebraska,  New  Jersey,  New 
York,  North  Dakota,  Ohio,  Pennsylvania,  South  Dakota,  Utah, 
Washington,  Wisconsin,  and  Wyoming  (fig.  1). 

DISTRIBUTION    IN    THE    DOMINION    OF    CANADA.1 

Quebec. — On  Comandra  umbellata.2 — Seven  Islands,  by  C.  B.  Robin- 
son (858,  Plants  of  Quebec). 

Ontario. — On  Comandra  umbellata.2 — London,  by  J.  Dearness  (2443, 
Sydow  Uredineen  and  3419,  Fungi  Columbiani) ;  and  Point  Abino, 
by  J.  J.  Davis  (Herbarium  New  York  Botanical  Garden). 

DISTRIBUTION    IN    THE    UNITED    STATES. 

Vermont. — On  Comandra  umbellata:  Between  Essex  Junction  and 
Burlington,  by  Hedgcock  (F.  P.  8539  and  8655) ;  locality  not  given, 
by  A.  J.  Grout  (Herbarium  New  York  Botanical  Garden). 

Massachusetts. — On  Comandra  umbellata:  Magnolia,  by  Seymour 
and  Earle  (210-a  and  210-b,  Economic  Fungi). 

New  York. — On  Comandra  umbellata:  Syracuse  (Ex.  Herbarium 
L.  M.  Underwood);  Ithaca,  by  H.  S.  Jackson  (1458,  Flora  North 
America);  Mount  Defiance,  by  Peck  (Herbarium  New  York  State 
Museum). 

New  Jersey. — On  Comandra  umbellata:  Newfield,  by  Ellis  (1082, 
Ellis  and  Everhart,  North  American  Fungi). 

Pennsylvania. — On  Comandra  umbellata:  Charteroak,  Hunting- 
don County,  by  Orton,  Adams,  and  Kirk  (9,  p.  25) ;  Petersburg, 
Huntingdon  County,  by  Hedgcock  (F.  P.  15637).  Greenwood 
Furnace,  Huntingdon  County,  by  Hedgcock  (F.  P.  15653,  15654,  and 
15657). 

Ohio. — On  Comandra  umbellata:  Cleveland,  by  B.  T.  Galloway. 

Illinois. — On  Comandra  umbellata:  Oregon,  by  M.  B.  Waite  (85, 
134,^176,  and  366). 

Missouri. — On  Comandra  pallida:  Emma,  by  C.  H.  Demetrio 
(4310,  Rabenhorst-Paczschke,  Fungi  Europasi  et  Extra-Europa?i) . 

Michigan. — On  Comandra  umbellata:  Ann  Arbor,  by  Holway  (504, 
North  American  Uredinales);  Ann  Arbor,  by  F.  L.  Scribner;  Ros- 
common,  P.  Spaulding  (F.  P.  15681). 

Wisconsin. — On  Comandra  umbellata:  Racine,  by  J.  J.  Davis;  The 
Dells,  by  Underwood  (Herbarium  New  York  Botanical  Garden). 

Nebraska. — On  Comandra  pallida:  Dismal  River,  by  Webber  (784, 
Fungi  Nebraskenses) ;  Hat  Creek  basin,  by  Webber*  (776,  Fungi 
Nebraskenses);  Lincoln,  by  R.  J.  Pool  (F.  P.  17045). 

1  All  specimens  here  listed  are  in  the  mycological  collections  of  the  United  States  Department  of  Agricul- 
ture unless  otherwise  noted. 

2  These  species  probably  should  be  Comandra  richardsiana  Fernald,  since  the  collections  were  made  in  the 
range  of  C.  richardsiana,  and  out  of  the  range  of  C.  umbellata  as  now  recognized. 


A   DISEASE   OF   FIXES    CAUSED   BY   CRONARTIUM    PYRIFORME.       11 

Wyoming. — On  Comandra  pallida:  Big  Horn  Mountains,  by  Wil- 
liams and  Griffiths  (298-a,  West  American  Fungi);  Bear  Lodge 
Mountains,  by  Griffiths  and  Carter.  (298,  West  American  Fungi); 
Centennial,  by  E.  T.  and  E.  Bartholomew  (3705,  Fungi  Columbiani); 
near  Medicine  Bow  River,  by  A.  Nelson  (1257,  Herbarium  University 
of  Wyoming) . 

South  Dakota. — On  Comandra  pallida:  Iroquois,  by  F.  A.  Williams 
(1914,  Fungi  Columbiani);  Black  Hills,  near  Custer,  by  Hedgcock 
and  Phillips  (F.  P.  15827  and  15828). 

North  Dakota. — On  Comandra  pallida:  Beaver  Lake,  by  J.  F. 
Brenckle  (78,  Fungi  Dakotenses). 

Colorado. — On  Comandra  pallida:  Boulder,  by  F.  E.  and  E.  S. 
Clements  (542,  Cryptogamse  Formationum  Coloradeiisium) ;  south  of 
Yuma,  by  H.  L.  Shantz,  U.  S.  Dept.  Agr.  Plant-Disease  Survey; 
Short  Creek,  Custer  County,  by  T.  D.  A.  Cockerell  (99  and  104,  Ellis 
Collection  in  Herbarium  New  York  Botanical  Garden);  Soldier 
Canyon,  by  J.  H.  Cowen  (168,  Ellis  Collection);  La  Veta,  by  C.  A. 
Crandall  (283,  Ellis  Collection);  Pagosa  Peak,  by  C.  F.  Baker  (22, 
Plants  of  Southern  Colorado);  also  by  F.  S.  Earle  (120,  Herbarium 
New  York  Botanical  Garden);  Sangre  de  Cristo  Mountains  near 
Westcliffe,  by  Hedgcock  (F.  P.  8082);  Steamboat  Springs,  by  Hedg- 
cock (F.  P.  3873  and  3889) ;  Monument,  by  Hedgcock  (F.  P.  3792, 
3839,  15948,  and  15950);  Palmer  Lake,  by  Hedgcock  and  Bethel 
(F.  P.  3794  and  3819);  Boulder,  by  Hedgcock  (F.  P.  15885);  Golden, 
by  Hedgcock  (F.  P.  15888);  Palmer  Lake,  by  Hedgcock  (F.  P.  15907 
and  15948);  Monument  Nursery,  by  Hedgcock  and  Pierce  (F.  P. 
15950). 

Utah. — On  Comandra  pallida:  Locality  not  given,  by  M.  E.  Jones 
(Herbarium  New  York  Botanical  Garden). 

Montana. — On  Comandra  pallida:  Helena,  by  F.  D.  Kelsey; 
Sandcoulee,  by  F.  D.  Kelsey  (2419,  Ellis  and  Everhart,  North 
American  Fungi);  Sandcoulee  (80,  Montana  Flora)  and  Helena  (61, 
Parasitic  Fungi  Montana),  by  F.  W.  Anderson;  Missoula,  by  Hedg- 
cock and  Kirkwood  (F.  P.  8021). 

Washington. — On  Comandra  pallida:  West  Klickitat  County,  by 
W.  W.  Suksdorf  (176,  Flora  of  Washington). 

California. — On  Comandra  umbellata:  Shasta  Springs,  by  W.  C. 
Blasdale  (6  North  American  Uredinales),  by  M.  A.  Howe  (101,  Fungi 
California),  Herbarium  New  York  Botanical  Gardens;  Mills  Ranch, 
Siskiyou  County,  by  Boyce  (F.  P.  15796);  Integral  Mine,  Shasta 
County,  by  Boyce;  Rocky  Gulch,  Siskiyou  County,  by  Meinecke; 
Weaverville  and  Brown  Creek,  Trinity  County,  by  Boyce;  Goosenest 
Mountain,  Siskiyou  County,  by  Boyce  and  Rider. 


12  BULLETIN   247,  U.    S.   DEPARTMENT   OF   AGRICULTURE. 

DISSEMINATION  OF  THE  FUNGUS. 

Cronartium  pyriforme  is  disseminated  by  means  of  its  three  spore 
forms — viz.,  seciospores,  uredimospores,  and  teliospores — each  form 
playing  an  important  role  in  maintaining  the  succession  of  generations 
between  pine  trees  and  Comandra  plants.  The  process  of  infection 
with  this  species  of  rust  does  not  differ  materially  from  that  of  the 
white-pine  blister  rust  (12). 

The  secia  on  the  table  mountain  pine  (Pinus  pungens)  in  Pennsyl- 
vania mature  from  the  middle  of  May  to  the  latter  part  of  June. 
Farther  north  on  the  jack  pine  (Pinus  divaricata)  they  bear  their 
spores  somewhat  later  in  the  season.  On  the  lodgepole  pine  (Pinus 
contorta)  and  the  western  yellow  pine  (Pinus  ponderosa)  from  Colorado 
to  Wyoming,  the  period  of  maturity  is  from  the  middle  of  June  to  the 
middle  of  July.  In  each  region  they  develop  earlier  on  slopes  of 
southern  exposure  and  at  lower  altitudes. 

The  seciospores  are  discharged  in  great  abundance  for  a  day  or  two 
and  with  lessened  abundance  for  about  a  week  longer.  They  infect 
any  Comandra  plants  with  which  they  come  in  contact.  The  leaves 
are  most  commonly  infected,  but  occasionally  the  stems  and  floral 
parts  are  attacked.  The  infection  near  diseased  pine  is  usually  very 
abundant,  decreasing  rapidly  as  the  distance  increases.  An  abundant 
infection  from  seciospores  has  not  been  noted  for  more  than  200  feet 
from  the  secial  center,  when  it  is  located  on  small  pines.  When  large 
pines  are  diseased  in  the  upper  limbs,  the  distance  that  the  seciospores 
are  blown  is  greatly  increased,  and  the  zone  of  infection  is  therefore 
extended  very  much,  and  on  mountain  slopes  may  reach  the  distance 
of  nearly  1,000  feet.  This  inoculation  of  Comandra  plants  by 
seciospores  may  well  be  designated  as  a  primary  infection,  and  that  by 
urediniospores,  described  in  the  following  paragraph,  as  a  secondary 
infection. 

In  8  to  10  days  from  the  time  of  inoculation  by  seciospores  the 
uredinia  appear  on  the  leaves  of  the  infected  Comandra  plants  and 
urediniospores  begin  to  be  produced.  These  are  blown  about  by 
winds  and  inoculate  other  Comandra  plants.  This  secondary  infec- 
tion greatly  extends  the  area  of  diseased  plants.  A  second  crop  of 
uredinia  develops  in  from  8  to  10  days  from  these  secondary  infections. 
This  process  continues  throughout  the  growing  season.  It  is  possible 
that  as  many  as  six  or  more  generations  of  uredinia  may  be  thus  pro- 
duced in  one  season,  and  the  fungus  may  spread  several  miles  in  this 
manner.  It  is  by  this  method  of  infection  that  the  fungus  spreads 
the  greatest  distance  in  nature,  which  explains  why  the  form  of  fungus 
on  the  Comandra  plants  is  more  common  than  on  the  form  of  pines. 

In  about  15  days  the  telial  columns  develop  from  the  uredinial  sori 
on  the  Comandra  plants.  As  each  column  grows  older  it  gradually 
elongates,  and  the  development  of  teliospores  progresses  outward 


A   DISEASE   OF   PINES    CAUSED   BY   CRONAETIUM    PYRIFORME.       13 

along  the  column  with  its  growth.  .The  period  of  teliospore  formation 
for  each  telium  is  from  one  to  two  weeks.  The  teliospores  germinate 
in  situ  as  fast  as  they  mature,  without  being  detached  from  the  telial 
columns.  As  each  teliospore  germinates  it  develops  a  basidium, 
which  when  typical  bears  four  sporidia.  The  sporidia  borne  on  each 
basidium,  however,  are  usually  less  than  four.  The  sporidia  become 
detached  as  soon  as  mature  and  are  carried  away  by  even  the  slightest 
breeze.  They  readily  infect  the  younger  part  of  pine  trees,  thus 
completing  the  life  cycle  of  the  fungus.  From  observation  it  appears 
probable  that  germinating  sporidia  usually  gain  entrance  into  the 
tissues  of  the  pines  through  wounds  or  in  wound  callus  where  young 
cells  are  exposed.  Inoculations  with  another  species,  Cronartium 
cerebrum,  on  pine  trees  (Pinus  virginiana)  without  wounds  have  failed, 
while  at  the  same  time,  other  conditions  being  similar,  they  were 
successful  in  wounds. 

Since  each  generation  of  uredinia  on  Comandra  plants  is  followed 
within  a  few  days  by  one  of  the  telia,  there  is  a  continual  produc- 
tion of  sporidia  from  the  time  the  telia  first  appear  till  the  end 
of  the  growing  season.  This  greatly  extends  the  period  of  pos- 
sible infection  for  pines,  a  period  which  must  be  from  two  to  four 
months,  depending  upon  the  length  of  the  growing  season  in  pines, 
which  varies  not  only  at  different  altitudes  and  in  different  latitudes, 
but  also  from  season  to  season. 

It  is  highly  probable  that  the  various  spore  forms  of  this  fungus, 
especially  the  seciospores  from  the  pines,  may  be  carried  about  on 
the  bodies  of  birds  and  of  the  smaller  animals.  In  this  manner  they 
could  be  carried  even  to  greater  distances  than  is  possible  by  wind 
dissemination. 

If  young  pines  in  nurseries  should  become  infected,  the  danger 
of  a  much  wider  dissemination  of  the  fungus  than  has  already  taken 
place  in  nature  is  at  once  possible,  with  man  as  the  agent.  Under 
conditions  such  as  occur  in  many  localities  both  in  the  eastern  and  the 
western  United  States  it  would  be  easily  possible  for  the  pines  in 
nurseries  to  become  badly  infected,  owing  to  the  abundance  of  Coman- 
dra plants  in  the  vicinity. 

EFFECT  OF  THE  FUNGUS  ON  ITS  HOST  PLANTS. 

EFFECT  OF  THE  ^ECIAL  FORM  ON  PINES. 

The  immediate  effect  of  the  aecial  form,  Peridermium  pyriforme, 
varies  in  different  species  of  pines  and  on  the  same  species  under 
different  conditions.  When  young  lodgepole  pines  or  western  yellow 
pines  are  attacked,  either  on  the  trunk  or  limbs,  there  commonly 
develops  a  slightly  swollen  area  in  the  region  of  the  infection.  If 
the  infected  area  encircles  the  trunk,  as  it  usually  does,  a  spindle- 
shaped  or  fusiform  swelling  may  result  (PL  II,  fig.  3),  which  varies 


14  BULLETIN   247,   U.    S.   DEPARTMENT   OF   AGRICULTURE. 

from  an  inch  to  more  than  a  foot  in  length.  In  case  of  Pinus  pungens 
(PL  II,  figs.  1  and  2),  fusiform  swellings  are  not  so  common  as  in 
case  of  Pinus  contoria  and  Pinus  ponderosa.  Swelling  is  commonly 
not  very  evident  in  very  young  trees  of  any  of  these  three  species. 
The  bark  layers  are  usually  thickened  in  the  portions  where  the  rust 
mycelium  is  present.  So  far  as  can  be  ascertained  from  field  observa- 
tions the  secia  may  not  appear  until  three  or  more  years  after  infection 
takes  place. 

The  development  of  the  peridia  at  the  maturity  of  the  aecia  rup- 
tures the  bark  of  the  diseased  areas,  forming  numerous  openings 
(PL  II,  fig.  2)  which  reach  to  the  inner  layers  of  the  cambium.  As  a 
result  the  death  of  the  cambium  layer  may  take  place,  due  apparently 
to  excessive  evaporation  of  water  through  the  lesions.  The  part  of 
the  tree  attacked  usually  is  either  girdled  and  killed  outright  or  it  is 
partially  girdled  and  a  canker  is  formed.  Young  pines  are  very 
commonly  girdled  and  killed  during  the  same  season  the  93cia  are 
produced.  In  its  effect  on  pines,  Peridermium  pyriforme  must  be 
classed  with  P.  strobi  and  P.  filamentosum  and  be  ranked  as  one 
of  the  most  destructive  species  of  Peridermium  in  North  America. 

In  a  region  adjacent  to  Greenwood  Furnace,  Huntingdon  County, 
Pa.,  the  senior  waiter,  during  June,  1914,  took  notes  on  the  number 
and  condition  of  pines  (Pinus  pungens)  diseased  with  Peridermium 
pyriforme.  Again,  in  autumn,  the  condition  of  the  same  trees  was 
noted,  and  it  was  found  that  of  50  diseased  pines  upon  which  the 
secia  had  been  found  in  June,  29  (58  per  cent)  were  dead  from  the 
girdling  effect  of  the  fungus. 

These  had  apparently  died  shortly  after  the  secia  fruited,  as  dead 
leaves  were  still  clinging  to  the  branches  of  the  trees.  The  pines  ex- 
amined were  small,  varying  in  height  from  4  to  10  feet,  and  in  diam- 
eter at  the  ground  from  1  to  4  inches.  A  similar  effect  was  noted 
during  the  autumn  of  1914  on  a  smaller  number  of  young  pines 
(Pinus  ponderosa)  in  the  Black  Hills  near  Custer,  S.  Dak. 

J.  S.  Boyce,  of  the  Office  of  Investigations  in  Forest  Pathology,  has 
reported  this  fungus  on  the  yellow  pine  (Pinus  ponderosa)  in  Klamath, 
Shasta,  and  Trinity  National  Forests  in  California.1  This  report 
states  that  in  the  Klamath  National  Forest — 

The  parasite  produced  spindle-shaped  swellings  at  the  point  of  infection  on  the 
yellow  pine,  usually  on  the  main  stem  but  occasionally  on  the  branches.  These 
swellings  varied  from  2  inches  to  a  foot  in  length. 

The  fungus  on  yellow  pine  undoubtedly  kills  that  portion  of  the  main  stem  or  branch 
of  the  tree  above  the  point  of  infection.  A  number  of  small  trees  were  found  to  have 
been  killed.  Each  of  these  bore  one  or  more  spindle-shaped  swellings  on  the  stem. 
A  volunteer  (shoot)  had  then  appeared  while  a  new  infection  had  occurred  just 
below  the  point  where  the  volunteer  joined  the  main  stem.  A  repeated  killing  of 
this  kind  causes  a  strikingly  deformed  tree. 

1  Boyce,  J.  S.    Notes  on  Cronartium  pyriforme.    Unpublished  report  submitted  December  7, 19H. 


A   DISEASE  OF   PINES   CAUSED  BY   CRONARTIUM   PYRIFORME.       15 

The  largest  infected  tree  found  was  12  feet  high  and  3  inches  in  diameter  at  breast 
height,  approximately  22  years  old,  with  the  infection  occurring  5  feet  from  the  ground. 
In  another  area  here  10  saplings  killed  by  the  fungus,  with  only  one  living  uninfected 
tree,  were  found. 

One  diseased  area  of  Pinus  ponderosa  at  Mills  Ranch  on  the  north 
slope  of  Goosenest  Mountain  in  the  Klamath  National  Forest  was 
described  by  Boyce,  which  contained  at  least  a  hundred  acres.  The 
largest  tree  diseased  by  the  fungus  in  this  area  was  8  inches  in  diame- 
ter at  breast  height.  Spindle-shaped  swellings  were  common,  but 
more  especially  on  the  younger,  smaller  trees.  The  girdling  effect 
and  death  of  the  host  tree  in  the  parts  above  the  point  of  infection 
were  very  much  in  evidence  in  this  area.  Small  trees  apparently 
were  girdled  and  killed  much  sooner  than  older  trees.  Wounds  caused 
by  some  gnawing  animal,  presumably  the  porcupine,  were  common 
on  trees  in  areas  where  the  fungous  disease  occurred.  In  one  of  the 
diseased  portions  of  the  forest  a  sample  plat  was  established  by 
Boyce  and  a  count  of  the  healthy,  infected,  dead,  and  dying  trees 
of  Pinus  ponderosa  was  made.  The  result  was  as  follows:  Out  of  314 
trees  in  the  plat,  153  (48.7  per  cent)  were  apparently  healthy,  52 
(16.5  per  cent)  were  plainly  diseased  by  the  fungus,  3  (0.9  per  cent)-" 
were  dying,  and  106  (33.7  per  cent)  were  dead  from  the  effects  of  the 
fungus.  In  the  words  of  the  report: 

Over  50  per  cent  of  the  total  number  of  trees  of  the  sample  plat  had  been  infected, 
and  nearly  two-thirds  of  the  total  number  infected  had  already  been  killed.  There  is, 
of  course,  a  possibility  that  the  death  of  some  of  these  might  have  resulted  from  other 
causes,  but  only  those  trees  were  included  which  I  was  certain  in  my  mind  had  been, 
killed  by  the  fungus. 

Boyce' s  data  corroborate  those  taken  by  the  senior  writer  both  in 
Pennsylvania  and  South  Dakota. 

Reporting  concerning  an  area  of  diseased  Pinus  ponderosa  along 
Browns  Creek  in  Trinity  National  Forest,  Boyce  says: 

There  were  many  dead  trees,  undoubtedly  killed  by  the  fungus,  with  spindle-shaped 
swellings  on  the  main  stems.  On  living  infected  trees  the  secia  were  sporulating 
(June  27,  1914),  but  not  very  abundantly,  not  to  be  compared  with  the  sporulation 
found  at  Rocky  Gulch  on  May  20.  One  infected  sapling  was  found  in  which  the 
major  portion  of  the  bark  had  been  destroyed  either  by  wood  rats  or  porcupines. 

Where  the  trunk  is  not  girdled,  cankers  or  catfaces  are  occasionally 
formed  by  the  death  of  a  portion  of  the  cambium.  In  such  cases 
the  continued  presence  of  the  fungus  in  the  live  tissues  beyond  the 
dead  area  stimulates  their  growth,  and  the  fungus  may  fruit  a  number 
of  times  before  the  tree  is  killed.  Catfaces  on  the  lodgepole  pine 
(Pinus  contorta)  and  on  the  western  yellow  pine  (Pinus  ponderosa), 
however,  are  more  commonly  produced  by  another  species  of  rust, 
Peridermium  Tiarlcnessii. 

Peridermium  pyriforme,  when  it  infects  the  trunk  of  a  pine  tree, 
may  spread  from  the  trunk  to  such  limbs  as  spring  from  a  point  near 


16  BULLETIN   247,   U.    S.   DEPARTMENT   OF   AGRICULTURE. 

the  center  of  infection  or,  vice  versa,  may  spread  from  the  point  of 
infection  on  a  limb  to  that  part  of  the  trunk  adjacent  to  the  diseased 
area  on  the  limb.  In  this  it  resembles  P.  filamentosum  (5)  and  the 
fusiform  type  of  P.  cerebrum  (P.  fusiforme)  (7,  p.  248).  Such  in- 
stances in  the  case  of  both  P.  pyriforme  and  P .  filamentosum  on  Pinus 
ponderosa  have  been  observed  by  the  senior  writer  in  Colorado  and 
Wyoming  and  noted  by  Spaulding  (11,  p.  28,  34)  in  the  case  of  Peri- 
dermium  strobi  on  white  pines  in  the  northeastern  United  States. 

EFFECT  OF  THE  UREDINIAL  AND  TELIAL  FORMS  ON  COMANDRA  PLANTS. 

The  effect  of  the  uredinial  and  telial  forms  of  the  fungus,  Cronartium 
pyriforme,  on  Comandra  plants  can  not  be  separated  into  two  distinct 
sets  of  symptoms,  since  the  two  forms  are  produced  on  the  same 
area  of  tissue,  the  one  following  the  other  in  a  few  days.  Both  the 
uredinia  or  the  telia  may  occur  on  either  surface  of  the  leaves,  as 
well  as  on  the  younger  portions  of  the  stems,  and  occasionally  on  the 
floral  parts.1  In  badly  infected  plants  there  is  a  decided  shortening 
of  both  the  stems  and  the  leaves  in  their  growth,  so  much  so  as  to 
change  the  entire  aspect  of  the  plants.  This  is  usually  accompanied 
by  a  slight  chlorosis  of  the  leaves.  Where  the  infection  is  slight,  the 
diseased  spots  on  the  leaves  are  usually  a  lighter  green  color  than  the 
uninfected  portions.  Late  in  the  growing  season  the  reverse  colora- 
tion sometimes  takes  place,  and  the  chlorophyll  is  retained  longest 
in  light-green  areas  in  the  leaves  where  the  mycelium  of  the  fungus 
is  found,  even  after  the  remainder  of  the  leaf  has  become  yellow  from 
fall  coloration. 

In  badly  infected  Comandra  plants  defoliation  takes  place  prema- 
turely; that  is,  before  drought,  frost,  or  cold  weather  bring  it  about. 
No  data  have  been  obtained  as  to  the  final  effect  of  the  rust  on 
Comandra  plants.  The  effect,  however,  is  decidedly  stunting,  and 
plants  infected  badly  for  several  seasons  would  undoubtedly  be  killed. 

ERADICATION  AND  CONTROL  OF  THE  FUNGUS. 

One  of  the  most  serious  facts  in  connection  with  the  prevalence  of 
Peridermium  pyriforme  in  some  portions  of  the  western  United  States 
is  the  danger  of  introducing  it  into  localities  now  free  from  it  through 
the  shipment  of  trees  in  the  work  of  artificial  reforestation.  For  this 
purpose  nursery  stock  is  often  shipped  long  distances.  The  forest 
nursery  if  situated  in  mountain  regions  is  apt  to  be  in  a  locality  where 
Comandra  plants  are  common.  Since  these  serve  as  host  plants  for 
both  the  uredinial  and  telial  forms  of  the  fungus,  their  presence  may 
lead  directly  to  the  infection  of  the  young  pines  in  the  nursery  and 
indirectly  to  the  infection  of  localities  hitherto  free  from  the  disease. 

i  IB  Comandra  pallida  this  is  the  case.    In  Comandra  umbellata  the  uredinia  and  telia  are  found  uniformly 
on  the  under  surface  of  the  leaves. 


A  DISEASE   OF   PINES   CAUSED  BY   CRONARTIUM    PYRIFORME.       17 

If  it  were  possible  to  distinguish  all  of  the  diseased  trees  at  the  time 
of  planting,  it  would  be  an  easy  matter  to  discard  them  and  thus 
prevent  the  further  spread  of  the  disease.  Such,  however,  is  not  the 
case,  since  the  disease  may  not  become  evident  until  three  or  four 
years  after  the  young  trees  are  infected  and  until  after  they  are  planted 
in  the  forest.  This  being  the  case,  other  means  for  the  control  of  the 
disease  must  be  adopted.  The  most  feasible  plan  to  prevent  further 
infection  in  the  nursery  and  the  subsequent  dissemination  of  the 
disease  through  infected  nursery  stock  appears  to  be  the  elimination 
of  all  Comandra  plants  in  the  vicinity  of  the  nursery. 

In  order  to  protect  the  nursery  from  infection  whenever  the  dis- 
ease is  present  in  adjacent  forests,  all  diseased  pines  that  can  be 
found  within  a  radius  of  at  least  half  a  mile  from  the  nursery  should 
be  cut  down.  These  can  be  selected  most  easily  by  a  person  familiar 
with  the  fungus,  at  the  time  the  secia  mature  in  the  pines.  As  pre- 
viously stated,  this  period  varies  from  the  middle  of  May  till  in 
August,  depending  upon  both  the  latitude  and  the  altitude  of  the 
locality.  This  cutting-out  process  should  be  repeated  each  year  until 
no  more  diseased  trees  can  be  found  in  the  proposed  neutral  zone. 

The  elimination  of  all  diseased  pines  will  not  suffice,  however, 
absolutely  to  control  the  disease  in  the  nursery  when  Comandra  plants 
are  in  the  vicinity,  since  it  is  quite  certain  that  the  fungus  can  spread 
by  the  urediniospores  from  one  Comandra  plant  to  another  for  long 
distances  in  one  season.  By  this  means  the  disease  could  be  carried 
from  diseased  pines  outside  of  the  neutral  zone  or  belt  of  removal  to 
the  young  pines  in  the  nursery.  To  protect  the  nursery  against  infec- 
tion from  this  fungus  all  Comandra  plants  within  1,000  feet  of  the 
outer  boundaries  of  the  nursery  should  be  removed  by  digging  them 
out. 

Comandra  plants  are  herbaceous  perennials  and  spread  primarily 
by  means  of  seeds  and  secondarily  by  means  of  underground  runners. 
The  secondary  method  is  the  more  common.  The  seeds,  being 
edible,  are  much  liked  by  birds  and  rodents,  and  it  is  possible  that 
they  may  bo  carried  by  these  animals  to  a  considerable  distance  from 
the  original  place  of  growth,  thus  starting  new  plant  colonies.  The 
eradication  of  Comandra  plant  colonies  will  be  difficult,  owing  to  the 
numerous  underground  runners,  any  of  which  are  liable  to  be  broken 
off  and  left  in  .the  ground  to  start  new  plants.  It  will  no  doubt  be 
necessary  to  dig  up  the  plants  repeatedly  before  they  can  be  com- 
pletely eradicated.  All  species  of  Comandra  are  parasitic  and  derive 
part  of  their  food  supply  from  other  plants  by  a  direct  attachment 
of  the  smaller  side  roots  of  Comandra  to  the  roots  of  the  host  plants. 
It  is  not  yet  known  how  many  species  of  plants  are  thus  parasitized, 
but  several  widely  different  species  are  attacked.  Species  of  Vac- 


18  BULLETIN   247,,   U.    S.    DEPARTMENT   OF   AGRICULTURE. 

cinium  are  commonly  parasitized.  This  subject  is  now  being  in- 
vestigated by  the  writers. 

The  recommendations  here  given  are  based  on  observations  made 
in  forests  by  the  senior  writer  and  not  on  actual  experiments.  An 
attempt  to  control  this  disease  as  recommended  here  has  been 
planned  and  will  probably  be  carried  out  in  1915.  Until  it  is  certain 
that  the  neighborhood  of  a  nursery  is  free  from  this  fungus,  ship- 
ment of  stock  to  uninfected  forests  should  be  avoided. 

The  spraying  of  pines  with  Bordeaux  mixture  or  other  fungicides 
for  the  prevention  of  infection  by  Cronartium  pyriforme  can  not  be 
recommended  until  it  is  known  that  this  method  is  effectual  in  con- 
trolling the  disease. 

The  spraying  of  Comandra  plants  with  a  poisonous  substance  to 
kill  the  foliage  and  tender  shoots  at  the  time  they  might  be  infected 
from  the  aecial  form  of  the  fungus  on  pines  should  prevent  the  imme- 
diate spread  of  the  disease  to  the  pines  in  adjacent  nurseries.  This 
spraying  should  be  done  as  soon  as  the  leaves  of  the  Comandra  plants 
are  fully  developed  and  before  the  plants  bloom.  This  would  prob- 
ably be  from  the  latter  part  of  May  to  the  middle  of  July,  depending 
on  the  altitude  and  the  latitude  of  the  locality.  Should  the  Coman- 
dra plants  send  forth  new  growth  later  in  the  season  it  might  be 
necessary  to  spray  a  second  time.  Spraying  should  be  repeated  each 
year  as  long  as  any  Comandra  plants  remain  alive.  Where  young 
pines  are  present,  this  method  could  not  be  used  without  killing  them, 
and  the  uprooting  of  the  Comandra  plants  is  recommended  for  such 
areas. 

Mr.  H.  R.  Cox,  Agriculturist  of  the  Office  of  Farm  Management, 
Bureau  of  Plant  Industry,  has  prepared  a  circular  letter  giving  direc- 
tions for  the  use  of  plant  poisons  in  killing  vegetation.  This  circular 
follows,  more  complete  directions  being  obtainable  from  the  office 
mentioned  upon  request: 

For  several  years  this  office  has  been  making  tests  of  various  chemical  plant  poisons 
for  killing  all  vegetation  in  such  situations  as  driveways,  pathways,  tennis  courts, 
railroad  rights  of  way,  and  similar  places.  It  appears  that  of  the  substances  there  are 
three  that  are  better  than  any  of  the  rest,  namely,  arsenite  of  soda,  common  salt,  and 
some  form  of  petroleum.  The  best  one  of  these  for  each  case  will  depend  upon  condi- 
tions. It  seems  to  be  more  economical  usually  to  make  a  number  of  comparatively 
light  applications  for  the  purpose  primarily  of  killing  the  foliage  rather  than  one  heavy 
one  to  affect  the  roots  as  well  as  the  tops. 

In  the  case  of  most  kinds  of  vegetation  excepting  the  grasses,  and  especially  for 
vegetation  of  a  broad-leafed  character,  arsenite  of  soda  is  highly  effective.  The  com- 
mercial grade  may  be  obtained  at  about  25  cents  per  pound  from  some  of  the  wholesale 
chemists.  If  large  areas  are  to  be  treated,  it  can  be  made  at  home  more  cheaply  by 
boiling  1  pound  of  white  arsenic  and  2  pounds  of  sal  soda  in  a  gallon  of  water  until 
a  stock  solution  is  formed.  From  10  to  20  pounds  of  the  commercial  arsenite  of 
soda  or  from  7  to  14  pounds  of  the  white  arsenic  in  the  home-mixed  formula,  either  one 
diluted  to  make  from  50  to  100  gallons  of  solution,  is  sufficient  to  kill  most  of  the  foliage 
on  1  acre. 


A  DISEASE   OF   PINES   CAUSED  BY   CRONARTIUM   PYRIFORME.       19 

Common  salt  may  be  applied  dry,  provided  it  is  fine  grained  and  is  scattered  very 
uniformly.  Salt  may  be  applied  more  uniformly,  however,  if-  it  is  made  into  a  satu- 
rated solution  (1  pound  to  1£  quarts  of  water).  The  latter  is  usually  the  most  satis- 
factory form.  It  should  be  used  at  the  rate  of  from  3  to  5  tons  per  acre,  depending 
upon  the  character  and  rankness  of  the  vegetation. 

Of  the  petroleum  products,  fuel  oil  is  about  the  most  satisfactory,  although  this  is 
sometimes  difficult  to  obtain,  and  then  only  in  barrel  or  tank-car  lots.  Near  the  oil 
fields,  crude  oil  as  it  comes  from  the  well  can  be  obtained  cheaply  and  is  quite  satis- 
factory. The  petroleum  products  should  be  applied  at  the  rate  of  from  300  to  400 
gallons  per  acre.  If  small  areas  are  to  be  treated,  so  that  the  matter  of  expense  is  of 
little  consideration,  kerosene  may  be  used.  The  petroleum  products  seem  to  be  the 
most  effective  of  all  when  applied  to  narrow-leafed  vegetation,  such  as  grass;  salt 
seems  to  be  the  next  in  effectiveness  on  such  plats,  and  arsenic  third. 

A  spraying  outfit  is  best  for  applying  liquid  material,  excepting  the  salt  brine,  with 
which  a  sprinkling  can  or  sprinkler  will  do  faster  work.  The  petroleum  products  are 
very  hard  on  the  rubber  parts  of  spraying  outfits,  but  it  is  necessary  to  use  a  sprayer 
in  that  connection  on  account  of  economy  of  application ;  with  very  small  areas  where 
economy  is  not  to  be  considered  the  oils  can  be  applied  through  a  sprinkling  can. 

In  the  forest  under  our  present  conditions  and  market  values  it 
is  not  best  to  advise  methods  of  elimination  so  expensive  as  have" 
been  given  for  the  protection  of  nurseries.  In  badly  infected  areas 
of  young  forest  trees,  all  diseased  trees  should  be  cut  out  whenever 
possible.  This  often  can  be  done  by  the  forest  officer  without  very 
great  expense,  owing  to  the  small  size  of  the  trees.  In  lumbering, 
trees  diseased  with  catfaces  or  cankers  should  not  be  left  for  seed 
trees,  as  their  vitality  has  been  lowered  and  they  will  not  produce 
as  good  a  crop  of  seed  as  more  healthy  trees,  and  it  is  also  highly 
probable  that  the  viability  of  the  seed  produced  by  such  trees  is 
lower  than  that  produced  by  more  healthy  trees.  Again,  trees  with 
such  cankers  are  often  capable  of  producing  seciospores  around  the 
border  of  the  cankers  and  if  allowed  to  remain  for  seed  trees  would 
become  centers  of  infection  for  the  younger  generations  of  trees  hi 
the  new  forest. 


20  BULLETIN   247,   V.    S.    DEPARTMENT   OF   AGRICULTURE. 

LITERATURE  CITED. 

(1)  ARTHUR,  J.  0.,  and  KERN,  F.  D. 

1906.  North  American  species  of  Peridermium.     In   Bui.    Torrey  Bot. 

Club,  v.  33,  no.  8,  p.  403^38. 
(2) 

1913.  The  rediscovery   of   Peridermium   pyriforme   Peck.     In   Science, 

n.  B.  v.  38,  no.  974,  p.  311-312. 
(3) 

1914.  North  American  species  of  Peridermium  on  pine.     In  Mycologia. 

v.  6,  no.  3,  p.  109-138. 

(4)  BRITTON,  N.  L. 

1889.  Catalogue  of  plants  found  in  New  Jersey.     In  Geol.  Surv.  N.  J. 
Final  Rpt.,  v.  2,  pt.  1,  p.  27-642. 

(5)  HEDGCOCK,  G.  G. 

1913.  Notes  on  some  western  Uredinese  which  attack  forest  trees.     II. 

In  Phytopathology,  v.  3,  no.  1,  p.  15-17. 
(6) and  LONG,  W.  H. 

1913.  An  undescribed  species  of  Peridermium  from  Colorado.     In  Phyto- 

pathology, v.  3,  no.  4,  p.  251-252. 
(7)  ' 

1914.  Identity  of  Peridermium  fusiforme  with  Peridermium  cerebrum. 

In  Jour.  Agr.  Research,  v.  2,  no.  3,  p.  247-249,  pi.  11. 


(8)- 


1914.  The  Alternate  Stage  of  Peridermium  Pyriforme.     3  p.     Washington, 

D.  C.     Privately  printed. 
(9)  ORTON,  C.  R.,  and  ADAMS,  J.  F. 

1914.  Notes  on  Peridermium  from  Pennsylvania.     In  Phytopathology, 

v.  4,  no.  1,  p.  23-26,  pi.  3. 

(10)  PECK,  C.  H. 

1875.  New  fungi  from  New  Jersey.  In  Bui.  Torrey  Bot.  Club,  v.  6,  no.  2, 
p.  13-14. 

(11)  SPAULDING,  PERLEY. 

1911.  The  blister  rust  of  white  pine.  U.  S.  Dept.  Agr.,  Bureau  of  Plant 
Industry  Bui.  206,  88  p.,  5  fig.,  2  pi.  (1  col.). 

(12)  TUBEUF,  CARL  VON. 

1914.  Bekampfung  der  Ribes-bewohnenden  Generation  des  Weymouths- 
kiefernblasenrostes.  In  Naturw.  Ztschr.  Forst-  u.  Landw., 
Jahrg.  12,  Heft  3,  p.  137-139. 


WASHINGTON  :   GOVERNMENT  PRINTING  OFFICE  :   1915 


Caylord  Bros. 

Makers 

Syracuse,  N.  Y. 
PAT.  JAN.  21,  1908 


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